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I suspect they retired the referral program because focusing their energies on GoogleClick made more sense, and their own referral program had many issues. So they're still doing referrals, just under the DoubleClick name.
I heard a speculative and unconfirmed rumour that there are a bunch of uncomfirmed and speculative rumours about GOOG.
That's true, my cousin's ex-boyfriend knows someone who used to work as a night janitor in a building that had a guy who's married to a woman that knows Matt Cutt's wife, and she's confirmed that.